The present invention relates to tissue ligation, and in particular a ligating band which releases a drug, for example a chemotherapeutic agent.
Endoscopic ligation is often used to treat polyps or other growths inside the body. For example, pre-malignant gastrointestinal mucosa are often removed using an endoscopic snare, and endoscopic ligation may be employed to remove surrounding residual or base tissue, particularly when biopsy of the earlier-removed tissue indicates a foci of cancer. In other cases, mucosa may be removed by delivering a ligating band to the base of the mucosa. The ligating band restricts blood flow to the ligated tissue, leading to eventual necrosis.
One problem with treating pre-malignant or malignant mucosa endoscopically is that the base of the malignancy may not undergo necrosis. If some malignant or pre-malignant cells are left surviving, there is a risk that the residual cancer cells will spread further. For this reason, many physicians opt for surgical treatment of such mucosa. However, surgical resection is not desirable or even possible for some patients, and surgical recision is a much more invasive and complicated procedure, even for more healthy patients.
A ligating band according to the present invention comprises an elastomeric layer and an inner drug releasing layer. The inner drug releasing layer includes a therapeutic agent, for example a chemotherapeutic agent. A ligating band according to the present invention also may include an inner diffusion barrier disposed between the elastomeric layer and the inner drug releasing layer, with the elastomeric layer and the inner drug releasing layer each contacting the inner diffusion barrier.